Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It explains the two charging phases (bulk and absorption) and that it works across charging sources. This provides useful context beyond the input schema, though it could mention assumptions like ideal battery behavior or temperature effects.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three sentences long, front-loaded with the main purpose, and every sentence adds necessary information. There is no fluff or repetition.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Despite the lack of an output schema, the description adequately explains the tool's behavior and inputs. It covers the key phases and source flexibility. It could be more complete by specifying output format (e.g., returns hours) or mentioning limitations, but it is sufficient for a calculator tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema covers 100% of parameter descriptions, so baseline is 3. The description adds value by explaining the charging phases, which gives context to the parameters (e.g., why targetSoC above 80% behaves differently). This goes beyond the schema's simple descriptions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool estimates charging time for a battery bank from a given state of charge to a target level. It uses a specific verb ('Estimate') and resource ('charging time'), and distinguishes itself from sibling calculators (e.g., calculate_battery_bank, calculate_solar_size) which focus on other aspects of system design.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly states it works for any charging source (solar, shore power, alternator), providing clear context for when to use. However, it does not mention when not to use it or suggest alternative tools, though none of the siblings appear to duplicate this functionality.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.